U.S. Pat. No. 4,889,362 discloses a reversible stabilizer pad for earth moving vehicles having a generally flanged first surface for engagement with gravel and soft earth, for example, and a resilient surface for engagement with concrete or asphalt. This patent describes the use of rubber pads on one side of the stabilizer pad for ground contact when the vehicle is on a finished surface, such as concrete or asphalt, and flanges with grouser points on the opposite side of the stabilizer pad for ground contact when the machine is on an unfinished but hard ground surface that requires that the pads dig into the surface in order to better anchor and stabilize the machine when encountering difficult digging conditions. The flanged side of the pad is unsuitable for contact with the finished surfaces since it could damage and/or mar such surfaces. The stabilizer pad is pivotally mounted to the end of an hydraulically operated arm such that the pad may be rotated to contact the ground with either the rubber pad side or the flange side facing down to contact the ground surface.
When the vehicle is moved into position, if extra stability is needed, the stabilizer arms, on which the pads are mounted, are hydraulically operated to move from a retracted position, in which the arms generally extend upwardly and out of the way, to a use position, in which the arms extend downwardly at an angle with the pads contacting the ground surface. The arms and pads, of course, are positioned to provide extra stability to the vehicle. When the vehicle is to be moved, the arms are lifted back to the retracted position, the vehicle is moved to a new operating location and the stabilizer arms are brought down into the use position again, if necessary.
In prior stabilizer pad constructions such as the one described in U.S. Pat. No. 4,889,362, there has been a tendency for the pad to self-flip when the earth moving machine pad support arm is lifted. The self-flipping problem relates primarily to flipping from flanged side down to rubber pad side down because the rubber pad side is typically much heavier than the flange side. When the pad inadvertently flips sides, an operator must manually flip the pad back so that the proper side is facing down. Frequently, however, the operator does not realize that the pad has self-flipped or, even if he/she realizes it, does not bother to fix it. Accordingly, the machine is used with the wrong side of the stabilizer pad in contact with the ground surface, which could result in increased hazard as well as increased wear of the rubber pads, leading to premature need for replacement. The self-flipping of the pad can be remedied with a securing or engaging bolt that is required to be secured in each position of the pad and to be disassembled and re-secured when the position of the pad is to be changed. This becomes time consuming and furthermore may involve parts that are easily lost. Further, the operator simply may not use the securing pin or bolt.
U.S. Pat. No. 4,889,362 discloses an automatically operatable latch that is adapted to rotate into an engagement with the pad when the pad is in a ground engaging surface, and furthermore adapted to automatically rotate by gravitational force out of engagement with the pad when the arm of the earth moving machine that supports the pad is lifted. In this way, when the support arm is lifted, the latch disengages from the pad and the pad is easily rotated to its opposite position. It has been found, however, that rocks, gravel and other debris frequently get caught in the automatic latch disclosed in U.S. Pat. No. 4,889,362 which can prevent the latch from releasing when the arm is lifted. In many stabilizer constructions, however, the pad must rotate to some extent when the arm is lifted in order to allow the piston of the arm to retract into the cylinder. Failure of the latch to release can thus result in damage to the arm or pad.
In prior art stabilizer pad constructions, there is also a tendency for the pad, when configured with the rubber pad side down, to engage the ground surface with the rubber surface at an angle to the ground rather than horizontal to the ground as desired. As shown in FIG. 19, when the rubber pad engages the ground surface at an angle, it results in uneven wear of the rubber pad and causes the operator of the vehicle to be jolted as the pad engages the ground surface.
It is an object of the present invention to provide an improved stabilizer pad/arm construction for a vehicle.
It is a further object of the present invention to provide a stabilizer pad/arm construction for an earth moving machine which will not flip sides unintentionally.
It is another object of the present invention to provide a self-flip prevention mechanism which can be easily added to virtually any stabilizer pad/arm construction.
It is another object of the present invention to provide a stabilizer pad/arm construction for an earth moving machine which will not jam.
It is yet another object of the invention to provide a stabilizer pad/arm construction for a vehicle which will index the pad with respect to the arm to allow the pad to make smooth contact with the ground surface.